The present invention relates to the dyeing of dye penetrable fabrics and, more particularly, relates to the dyeing of tufted pile fabrics, such as carpeting, in a continuous process after the fabric has been tufted or woven.
In many cases it is desired to produce a variegated pattern of colors in which different hues or shades "fade in" at controlled portions of the fabric. These variegated patterns may be uniformly displaced throughout the fabric or may be used to create a changed effect across the width of the fabric. Usually it is desired that, unless the changes in hue or shade are accomplished along a sharp line as in printed fabrics or oriental carpets, the fade-in is "soft," not defining any distinct line of change.
Quite obviously, the use of the variegated color patterns in carpeting is quite limited therefore a manufacture also desires a dyeing machine that would be able to produce solid colors. For this reason, a machine capable of producing these variegated color patterns should also be capable of dyeing in a single hue.
With respect to the dyeing of carpets, there are several prior art techniques. The traditional method is to dye the yarns before they are woven or tufted to form the carpet. While this technique enables the production of intricate patterns and eliminates a separate dye step after the tufting of carpets, it also has several disadvantages. These include the difficulty of obtaining precise color matches, the necessity to decide on color mix of a final carpet product prior to tufting and, above all, the high cost of colored yarns. As a result, it is common practice to dye carpets after they have been tufted.
One method of dyeing carpet is a dye beck system. In the dye beck system, a roll of carpet is unrolled into a large stainless steel chamber. The carpet is looped around stainless steel feed rolls and immersed in a hot dye solution in the lower portion of the chamber. The carpet is continuously looped into the solution for a cycling time, typically an hour, after which it is placed in a stainless steel buggy to be transported to a dryer to dry. Thus, the dye beck is said to operate on a noncontinuous basis.
Another present system being utilized is the Kuster applicator using a doctor bar. The Kuster applicator has difficulty in operating at a wide viscosity range (of dye substances).
Another system is a standard pad machine. The pad machine exhibits difficulties in obtaining an even coating, presumably because of differences in pressures exerted by the pad along the carpet roll face. This results in light and dark shades along the length of carpet.